A city bus that Ashok Leyland has just unveiled could help attract the focus again to battery swapping, a cheaper method to operate electric vehicles provided there is infrastructure to replace their power cells frequently. The 'Circuit S', which Ashok Leyland is showcasing at the ongoing Auto Expo 2018, is cheaper to buy as well as operate, compared with other electric buses, the Hinduja Group company claimed. Its vehilce has just one lithium ion battery, compared with a pack of cells in other electric city buses.

A problem with the single battery is that it needs to be recharged at short intervals, but in city buses, that can be addressed by changing the battery at the layover time. Since the battery pack accounts for 50-60% of the cost of electric vehicles, swapping helps reduce the bus price, said the company.

The idea of running large vehicles using battery swapping was initially proposed by Ashok Jhunjhunwala, a professor at IIT-Chennai and adviser to the union government on electric mobility. But many had scoffed at the idea due to unavailability of associated infrastructure.

Ashok Leyland, India's largest bus maker, took up the challenge to prove the critics wrong by making a commercially viable bus based on battery swapping. It developed the Circuit S in partnership with Sun Mobility, a company co-founded by Chetan Maini — the man behind India's first electric car, Reva.

The bus is targeted at operators plying on city routes. City buses have fixed route kilometers, so the battery can be changed between trips.

According to Ashok Leyland, as much as 85% of the city routes in India are shorter than 35 km. In 60% of cases, it is less 20 km. The city bus requirement in India is estimated at 7,500-10,000 a year. The company estimates that buses based on battery swapping have the potential to corner 6,000-8,000 of that market.

A 500-kg battery in the Circuit S bus can be replaced in 2.5 minutes, Ashok Leyland managing director Vinod Dasari said. He said the company will not limit its focus to city buses alone. As volume picks up, there is a sizeable opportunity to scale up battery swapping to school buses, shift buses, and even long-distance buses, he said.

Under the current plan, Ashok Leyland will provide the bus while Sun Mobility will arrange support infrastructure and services such as charging stations and reinstalling of the battery. Ashok Leyland will pay Sun Mobility on the basis of the electricity consumed to recharge the batteries.

Sun Mobility vice-chairman Maini said battery swapping was never tried on such a large scale anywhere in the world. The two companies are offering the entire solution for city bus operators.

ET View: Deploy Solar Chargers

The move makes excellent sense. A dependable battery swap scheme can purposefully fast-forward usage of EVs nationally. The way forward is to install solar-powered chargers, especially in dense urban centres to begin with. It would be path-breaking. Solar-powered chargers for EVs would proactively bring down the carbon footprint in transportation. Note that Delhi Metro plans to draw power from the 750-MW Rewa ultra mega solar project in MP.